There no reason your couldn't put a G-26 in this plane, however the G-26 many require you to cut up a lot of the cowling due to it's size compared to a glow engine. Here's a link to the [link=http://www.seagullmodels.com/Admin/cgi-bin/SanphamImage/SACH%2083.pdf]Instruction Manual[/link], see if there's any pictures in there showing some firewall dimensions or cowling measurements.